Seal for covered tank floating roof



April 22, 1969 c, THQMPSON ET AL 3,439,829

SEAL FOR COVERED TANK FLOATING ROOF Filed Oct. 9, 1967 FIG./

IN VE N TORS l8 JOSEPH c. THOMPSON MILTON w. HEISTERBERG Patented Apr. 22, 1969 US. Cl. 220-26 8 Claims ABSTRACT OF THE DISCLOSURE There is disclosed a covered tank for storing liquids, such as petroleum products, also having therein a floating roof, the tank including an upstanding substantially cylindrical side wall and the floating roof being arranged in the tank and including an upstanding substantially cylindrical wall structure having an annular rim spaced radially inwardly from the tank side wall and defining an upstanding substantially annular space therebetween; sealing structure for the annular space comprising a substantially annular sealing element arranged in the annular space and carried by the rim and movable therewith with respect to the tank side wall, the sealing element being generally wedge-shaped in cross-section and having a top wall and a bottom wall converging outwardly and terminating in a juncture providing a bearing surface disposed in sliding sealing engagement with the tank side wall.

The present invention relates to sealing structure for storage tanks and particularly to sealing structures for covered tanks for storing liquids, such as petroleum products, having therein a floating roof.

It is an important object of the present invention to provide in a tank for storing liquids such as petroleum products an improved sealing structure, the tank including an upstanding substantially cylindrical side wall and a floating roof arranged therein and including an upstanding substantially cylindrical wall structure spaced radially inwardly from the tank side wall and defining an upstanding substantially annular space therebetween; a sealing structure for the annular space comprising a substantially annular sealing element arranged in the annular space and carried by the wall structure and movable therewith with respect to the tank side wall, the sealing element having a body tapering from a base portion disposed adjacent to the cylindrical wall structure toward a bearing surface disposed in sliding sealing engagement with the tank side wall, a top flange extending radially inwardly from the base of the body and over the upper edge of the Wall structure, a first mounting flange integral with the inner edge of the top flange and extending downwardly along the inner surface of the wall structure, a second mounting flange integral with the base and extending along the outer surface of the wall structure and substantially parallel to the first mounting flange and disposed in lateral alignment therewith, and fastener means interconnecting the first and second mounting flanges and wall structure to mount the sealing member upon the wall structure with the bearing surface of the sealing member disposed in sliding sealing engagement with the tank side wall.

In connection with the foregoing object, it is another object of the invention to provide in the combination set forth fastener means including a clamp bar disposed adjacent to the outer surface of the second mounting flange and carrying a plurality of threaded openings therein in register with aligned holes in the mounting flanges and the wall structure, and a corresponding plurality of bolts extending through the aligned holes and engaging the threaded openings to mount the sealing member upon the wall structure.

Another object of the invention is to provide an improved tank structure of the type set forth wherein the sealing element is formed of a plurality of extruded sections of resilient synthetic organic plastic resin, the preferred resin being a copoly'mer of 'butad-iene and acrylonitrile resins.

A further object of the invention is to provide in a tank of the type set forth an improved sealing element that is generally wedge-shaped in cross section and having a top wall and a bottom wall converging outwardly and terminating in a juncture providing a bearing surface disposed in sealing engagement with the associated tank side wall, the top wall extending radially inwardly over the upper edge of the associated rim on the floating roof, a first mounting flange integral with the inner edge of the top wall and extending downwardly along the inner surface of the rim, a second mounting flange integral with the bottom wall and disposed against the outer surface of the rim and extending upwardly along the outer surface of the rim substantially parallel to the first mounting flange and disposed in lateral alignment therewith, a reinforcing web interconnecting the top and bottom walls intermediate the ends thereof and being disposed generally parallel to the mounting flanges, and fastener means interconnecting the mounting flanges and the rim to mount the sealing member upon the wall structure with the bearing surface of the sealing member disposed in sliding sealing engagement with the tank side wall.

Further features of the invention pertain to the particular arrangement of the elements of the sealing structure, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a view in vertical section through a covered tank having therein a floating roof provided on the periphery thereof with a Sealing structure made in accordance with and embodying the present invention; and

FIGURE 2 is an enlarged fragmentary view in vertical section of that portion of FIG. 1 within the circle designated by the numeral 2, and illustrating the details of construction of the sealing structure of the present invention.

Referring now to FIGS. 1 and 2. of the drawing, there is illustrated a tank 10 for storing liquids, such as petroleum products, that includes an upstanding substantially cylindrical side wall 11 mounted upon a suitable base 12 and carrying on the upper portion thereof a covering roof 13 that is generally conical in shape and extends outwardly beyond the side Wall 11 and is provided with the usual manhole 14 therein, the manhole 14 being provided with the conventional cover 15. The tank 10 further comprises the usual outlet fixture 16 and a plurality of posts 17 which serve to support the covering roof 13 and also serve as guides for vertical movement of a floating roof 20 disposed within the tank 10.

The floating roof 20 is generally annular in shape and of piston-like construction, and as illustrated is arranged in the tank 10 in floating relation with the stored liquid therein indicated at 18; whereby the floating roof 20 rises and falls with respect to the side wall 11 of the tank 10 in accordance with the head of the body of liquid 18 stored therein. As illustrated, the floating roof 20 is of the pan type and comprises structure defining a float 22, the

float22 being formed by a substantially flat circular plate and an outer upstanding annular rim 26 with an inwardly directed flange 24, the parts 24 and 25 and 26 being suitably secured together, as by welding, to provide a structure that constitutes the float 22 that is adapted to float upon the surface of the liquid 18 within the tank 10. The annular rim 26 further includes an annular rim portion 27 disposed above the flange 24 and having an outer upstanding annular surface 28 and an inner upstanding annular surface 29. As illustrated, the outer annular surface 28 of the rim 27 is spaced radially inwardly from the tank side wall 11, and specifically the inner surface 19 thereof, to define an annular space therebetween extending completely around the floating roof 20.

The annular rim 27 on the floating roof 20 carries sealing structure including a sealing element 30 embodying the features of the present invention and essentially comprising a substantially annular resilient member arranged in the annular space between the walls 19 and 28 and located principally above the level of the stored liquid 18. The sealing element 30 more specifically comprises a body of flexible and resilient material, the preferred material being an expanded synthetic organic plastic resin, such for example as a copolymer of butadiene and acrylonitrile resins, suitable resins being that sold under the trademark Buna N or that sold under the trademark Rubatex, or the equivalent.

Preferably the sealing element 30 is formed as a continuous extrusion of the resin shaped to provide a top wall 31 and a bottom wall 32 that converge radially out- Wardly and provide a thickened juncture 33 having a bearing surface 35 that is disposed in sliding sealing engagement with the tank side wall 11 and specifically the inner surface 19 thereof. Since the completed sealing element 30 is actually annular in shape, relatively short sections having the extruded shape of FIG. 2 are cemented in place during the construction of the tank 10 in the field to provide a continuous annular ring which at any point has a cross section along a diameter of the tank 10 of the shape generally illustrated in FIG. 2. It will be understood that before engagement of the bearing surface 35 with the tank side Wall 11, the top wall 31 of the sealing element 30 is arranged substantially horizontally, while the bottom 32 extends outwardly and upwardly toward the juncture 33 with the top wall 31. The top Wall 31 extends radially inwardly and over the upper edge of the rim 27 and carries on the inner edge thereof a first mounting flange 36 which is disposed substantially normal to the top wall 31 and extends downwardly along the inner surface 29 of the rim 27. The inner edge of the bottom wall 32 carries a second mounting flange 37 integral therewith and extending upwardly therefrom, the mounting flange 37 being disposed against the outer surface 28 of the rim 27 and substantially parallel to the first mounting flange 36 and disposed in lateral alignment therewith. The sealing element 30 further comprises a pair of spaced-apart webs 38 and 39, the web 38 being disposed outwardly toward but spaced from the juncture 33 between the walls 31 and 32 and substantially normal to the top wall 31, while the reinforcing web 39 is disposed toward but spaced from the mounting flanges 36-37 and is also disposed substantially normal to the top wall 31. The reinforcing webs 38 and 39 provide a desired degree of rigidity in the sealing element 30 and in effect provide a relatively stifl body having on the outer annular edge thereof the bearing surface 35 and having on the inner annular edge thereof the mounting flanges 36 and 37.

Fastener structure is provided to mount the sealing element 30 upon the wall structure comprising the rims 26-27 of the floating roof 20 so as to hold the bearing surface 35 of the sealing member 30 disposed in sliding sealing engagement with the tank side wall, thus to seal the annular space between the tank side wall 11 and the rim 26 above the surface of the stored liquid 18. To this end aligned holes are provided at regular intervals through the rim 27 and the mounting flanges 36-37. There is provided against the outer surface of the mounting flange 37 a clamp bar 40 having opening therein in alignment with the holes in the flange 37 and with threaded nuts 41 arranged in registry with those holes. A washer bar 45 is provided against the inner surface of the mounting flange 36 and having openings therein in alignment with the holes in the flange 36, the washer bar 45 having a plurality of washers 46 suitably secured thereto as by welding and having openings therein in alignment with the openings in the 'washer bar 45. Finally, there is provided a bolt 50 having a threaded shank 51 pointed at one end as at 52 and carrying on the other end the usual hexagonal head 53, the shank 51 of the bolt 50 extending through the aligned openings in the associated washer 46 and the washer bar 45, and through the associated aligned holes in the rim 27 and the mounting flanges 36-37, and through the associated opening in the clamp bar 40 and threadedly engaging in the associated nut 41 on the clamp bar 40. In this manner, the bolt 50 serves to clamp the mounting flanges 36 and 37 against the rim 27 and between the clamp bar 40 and the washer bar 45. It will be understood that the clamp bar 40 and the washer bar 45 are formed as generally rectangular pieces of metal that are then curved to conform to and to have a radius of curvature substantially equal to the radius of curvature of the rim 27, preferably the bars 40 and 45 having convenient lengths, such as for example 3 feet, whereby a plurality of the bars 40 and 45 is provided around the periphery of the floating roof 20, the nuts 41 and the washers 46 preferably being disposed approximately every 9 inches therealong.

In the construction of the floating roof 20, and specifically in the mounting of the sealing element 30 thereon, the pointed ends 52 of the bolts 51 can actually be forced through the mounting flanges 36-37, whereby it is necessary to drill holes only in the rim 27, the clamp bar 40 and the washer bar 45 being pre-assembled elements with the necessary holes already drilled therein prior to transport to the site for assembly of the tank 10. The clamp bar 40 can be easily inserted into its operative position by virtue of the cross section of the sealing element 30. As a result, the labor required to assemble the sealing element 30 onto the floating room 20 is minimized thus to provide a structure that can be inexpensively assembled.

It will be appreciated that the sealing element 30 provides a good seal between the tank side wall 11 and the rims 26-27 due to the cross section thereof, the cross section being substantially wedge-shaped with additional rigidity provided where needed by the reinforcing webs 38-39. As a consequence, the sealing element 30 has a good service life, while being inexpensive to manufacture and assemble onto the floating roof 20.

In a preferred constructional example of the sealing element 30, the distance between the bearing surface 35 and the inner surface of the mounting flange 36, i.e., the overall length of the top wall 31, is 9 inches; the thickness of the top wall 31 and the bottom wall 32 is A inch; the thickness of the reinforcing Webs 38-39 is inch; the thickness of the mounting flanges 36-37 is inch; the vertical extent of the bearing surface 35 is inch; the vertical extent of the mounting flange 36 is 1% inches; the outer surface of the reinforcing web 38 is disposed 2% inches from the juncture of the walls 31-32; and the distance between the outer surface of the mounting flange 37 and the inner surface of the reinforcing web 39 is 2% inches.

'From the above it will be seen that there has been provided in a covered tank for storing liquids, such as petroleum products, and including a floating roof, an improved sealing structure for the annular space disposed between the upstanding annular side wall of the tank and the upstanding annular rim of the floating roof.

What is claimed is:

1. In a tank for storing liquids such as petroleum products, including an upstanding substantially cylindrical side wall, and a floating roof arranged in said tank and including an upstanding substantially cylindrical wall structure spaced radially inwardly from said tank side wall and defining a vertically extending substantially annular space therebetween; sealing structure for said annular space comprising a substantially annular sealing element arranged in said annular space and carried by said wall structure and movable therewith with respect to said tank side wall, said sealing element having a body tapering from a base portion disposed adjacent to said cylindrical wall structure toward a bearing surface disposed in sliding sealing engagement with said tank side wall, a top flange carried by said sealing element and extending radially inwardly from the base of said body and over the upper edge of said Wall structure, a first mounting flange integral with the inner edge of said top flange and extending downwardly along the inner surface of said wall structure, a second mounting flange integral with said sealing element base portion and extending along the outer surface of said wall structure and substantially parallel to said first mounting flange and disposed in lateral alignment therewith, and faster means interconnecting said first and second mounting flanges and said wall structure to mount said sealing member upon said wall structure with the bearing surface of said sealing member disposed in sliding sealing engagement with said tank side wall.

2. In a tank for storing liquids, as recited in claim 1, the combination wherein said fastener means including a clamp bar disposed adjacent to the outer surface of said second mounting flange and carrying a plurality of threaded openings therein in register with aligned holes in said first and second mounting flanges and said wall structure, and a corresponding plurality of bolts extending through said aligned holes and engaging said threaded openings to mount said sealing member upon said wall structure.

3. In a tank for storing liquids, as recited in claim 1, the combination wherein said sealing element is formed of a plurality of extruded sections of expanded resilient synthetic organic plastic resin.

'4. In a tank for storing liquids, as recited in claim 3, the combination wherein said synthetic organic plastic resin is a copolymer of butadiene and acrylonitrile resins.

5. In a tank for storing liquids such as petroleum products, including an upstanding substantially cylindrical side wall, and a floating roof arranged in said tank and including an upstanding substantially cylindrical wall structure having an annular rim spaced radially inwardly from said tank side wall and defining a vertically extending substantially annular space therebetween; sealing structure for said annular space comprising a substantially annular sealing element arranged in said annular space and carried by said rim and movable therewith with respect to said tank side wall, said sealing element being generally wedge-shaped in radial cross section and having a top wall and a bottom wall converging outwardly and terminating in a juncture providing a bearing surface disposed in sliding sealing engagement with said tank side wall, said top wall extending radially inwardly and over the upper edge of said rim, a first mounting flange integral with the inner edge of said top wall and extending downwardly along the inner surface of said rim, a second mounting flange integral with said bottom wall and disposed against the outer surface of said rim and extending upwardly along the outer surface of said rim substantially parallel to said first mounting flange and disposed in lateral alignment therewith, a reinforcing web interconnecting said top and bottom walls intermediate the ends thereof and being disposed generally parallel to said mounting flanges, and fastener means interconnecting said first and second mounting flanges and said rim to mount said sealing element upon said wall structure with the bearing surface of said sealing member disposed in sliding sealing engagement with said tank side wall.

6. In a tank for storing liquids, as recited in claim 5, the combination wherein two reinforcing webs are provided interconnecting said top and bottom walls at intervals therewith, said reinforcing webs being spaced apart and spaced inwardly from said edges of said top and bottom walls and disposed substantially parallel to said mounting flanges.

7. In a tank for storing liquids, as recited in claim 5, the combination wherein said top wall is arranged substantially horizontally and said bottom wall extends radially outwardly and upwardly with respect to said rim, and said mounting flanges and said reinforcing web are disposed substantially normal to said top wall.

8. In a tank for storing liquids, as recited in claim 5, the combination wherein said top wall has a radial extent of about 9 inches, said top and bottom walls and said reinforcing web have a thickness of about 4 inch, said mounting flanges have a thickness of about inch, and said bearing surface has a vertical extent of about inch.

References Cited UNITED STATES PATENTS 2,023,308 12/1935 Cantacuzene 22026 2,718,977 9/ 1955 Wiggins.

2,914,212 11/1959 Fino.

3,158,667 11/1964 Michaels 22026 X 3,333,725 8/ 1967 Hirata et al.

JOSEPH R. LECLAIR, Primary Examiner.

JAMES R. GARRETT, Assistant Examiner. 

